渤海莱州湾地区晚更新世以来有孔虫特征反映的古环境变化

Controlled by climate changes, there were three large-scale transgressions and regressions around the Bohai Sea during the late Quaternary, which were accepted by most geologists. However, a big controversy still exists about the time when the transgressions occurred separately. In order to find out the process of the paleoenvironmental changes around the Bohai Sea in the late Quaternary, the foraminifera assemblages from a new borehole Lz908 in the southern coast of the Laizhou Bay were studied, and then the transgressive strata were indentified. Combined with accelerator mass spectrometry radiocarbon 14C（AMS14C） and optically stimulated luminescence（OSL） ages, the occurrence time of these transgressions were re-determined. The result showed that three major large-scale transgressions occurred separately at the beginning of marine isotopic stage 7（MIS7）, the last interglacial period（MIS5） and the Holocene. In addition, a small-scale transgression occurred in the mid-MIS6, and the corresponding transgressive stratum was deposited. The transgressive deposition of MIS3 was also discovered in this study. However, the characteristics of the foraminifera indicated the environment during this period was colder than that in the MIS5. By comparison with the global sea-level changes, the paleoenvironmental changes around the Bohai Sea in the late Quaternary can be consistent with the global climate changes.     

中国近海海平面变化与ENSO的关系

利用中国沿海台站潮位和中国近海及赤道太平洋的卫星测高、海表温度、风及气压资料,分析了中国近海海平面变化与ENSO的关系。分析结果表明:中国沿海海平面季节变化受ENSO影响明显,在厄尔尼诺事件期间,中国沿海海平面Sa分潮的振幅明显减小,其中年振幅的历史极小值均出现厄尔尼诺年,不同区域历史极小值出现的年份不同;另外,中国沿海Sa分潮的振幅对厄尔尼诺事件的响应与其强弱有关,在强事件中,响应区域和幅度较大,弱事件中,响应区域和幅度偏小。在厄尔尼诺年,中国沿海海平面多低于相邻年份,并且其年际变化存在明显的2~3a、4~7a、准9a、11a和准19a的周期,其中4~7a的周期在冬春季节震荡最显著,其震荡幅度接近2cm。中国近海海平面与赤道东太平洋区域的海表温度年际变化之间存在反相关关系,其相关系数为-0.42;同时与Nio4和Nio3.4指数序列也呈现反相关关系。针对典型的1997/1998年尼诺事件发生前后的风场和气压场分析发现,尼诺发生前的冬半年,冬季风偏强,气压梯度加强,中国沿海海平面偏低;到了厄尔尼诺的盛期,出现较强的南风异常,气压梯度反向,季风转向,过渡到了厄尔尼诺事件的衰减期,为拉尼娜事件做准备,此时海平面偏高。     

Origin and anatomy of two different types of mass–transport complexes: A 3D seismic case study from the northern South China Sea margin

Integration of 2D and 3D seismic data from the Qiongdongnan Basin along the northwestern South China Sea margin has enabled the seismic stratigraphy, seismic geomorphology and emplacement mechanisms of eight separate, previously undocumented, mass–transport complexes (MTCs) to be characterized. These eight MTCs can be grouped into two types:(1) Localized detached MTCs, which are confined to submarine canyons and cover hundreds of km², consist of a few tens of km³ remobilized sediments and show long striations at their base. They resulted from small-scale mass-wasting processes induced by regional tectonic events and gravitational instabilities on canyon margins.(2) Regional attached MTCs, which occur within semi-confined or unconfined settings and are distributed roughly perpendicular to the strike of the regional slope. Attached MTCs occupy hundreds to thousands of km² and are composed of tens to hundreds of km³ of remobilized sediments. They contain headwall escarpments, translated blocks, remnant blocks, pressure ridges, and basal striations and cat-claw grooves. They were created by large-scale mass-wasting processes triggered by high sedimentation rates, slope oversteepening by shelf-edge deltas, and seismicity.Our results show that MTCs may act as both lateral and top seals for underlying hydrocarbon reservoirs and could create MTC-related stratigraphic traps that represent potential drilling targets on continental margins, helping to identify MTC-related hydrocarbon traps.     

基于GPS反射信号技术的渤海海冰实验

传统的海冰检测手段都存在着受天气影响或实时检测成本太高的缺点,为了更实时有效的检测海冰,减轻海冰灾害对于我国的影响,并达到防灾减灾的目的,本文研究了GPS反射信号(GPS-R)技术检测海冰的可能性。通过对2013年2月下旬在中国天津渤海湾的岸基架设GPS信号接收机所接收的观测数据进行分析,使用不同特性的反射海域(几乎全为海水或是海冰)的数据进行比对分析,其结果显示极化比值(反射左旋信号与直射右旋信号的比值)能够明显反演海冰密集度。本文首次将GPS-R技术应用于国内自主设计的渤海海冰检测实验中。     

HY-2 扫描辐射计风速数据产品与平台基观测数据的比较研究

基于南海北部PY30-1平台上2012年2月至9月测风仪观测的风速数据,开展了HY-2扫描辐射计风速数据比较研究。选取时空匹配窗口为5 min和25 km,利用HY-2扫描辐射计RM 100,70和35 km分辨率3种风速数据,分别与平台观测数据进行了比较。比较结果表明:在南海北部海域,HY-2扫描辐射计100 km分辨率风速和平台观测风速的均方根偏差为3.86 m/s;70 km分辨率风速和平台观测风速的均方根偏差为10.52 m/s;35 km分辨率风速和平台观测风速的均方根偏差为5.54 m/s。还进一步比较了有雨和无雨两种情况下HY-2扫描辐射计和平台数据的偏差,结果表明:有雨和无雨条件下都是100 km分辨率的数据偏差最小。这为在我国南海北部海域应用HY-2扫描辐射计的风速数据产品的选择提供了依据。     

近50年来杭州湾七姊八妹列岛海域海床演变分析

七姊八妹列岛海域位于杭州湾南部的灰鳖洋内,除了岛礁周围局部存有深沟外,其余地区海床平缓.为了探究该海域海床演变情况,在了解杭州湾来水来沙特征基础上,分析了七姊八妹列岛海域的水动力、悬沙和底质分布特征.不同时期海图的对比分析表明,该海域近岸水深较小,人类活动频繁,围涂筑堤工程较多,一直处于淤积状态,属淤涨型岸滩,而离岸较远的海域,泥沙难于落淤而随潮反复搬运,基本处于冲淤平衡状态.1962～2008年这46 a间,七姊八妹列岛海域总体呈现与岸线走向一致的淤积、冲刷间隔分布的冲淤带.平均淤积厚度约2.2 m,淤积幅度约5.0 cm/a,大多数地方平均冲刷厚度约2.4 m,冲刷幅度约5.0 cm/a.这些特点与当地的水动力条件和泥沙沉积特性相一致.     

海杂波微弱目标分形检测

The target on the sea surface is complex and difficult to detect due to the interference of backscattered returns from the sea surface illuminated by the radar pulse. Detrended fluctuation analysis （DFA） has been used successfully to extract the time-domain Hurst exponent of sea-clutter series. Since the frequency of the sea clutter mainly concentrates around Doppler center so that we consider to extract frequency-do- main fractal characterization and then detect a weak target within sea clutter by using the difference of frequency-domain fractal characterization. The generalized detrended fluctuation analysis （GDFA） is more flexible than traditional DFA owing to its smoothing action for the clutters. In this paper, we apply the GDFA to evaluate the generalized Hurst exponent of sea-clutter series in the frequency domain. The difference of generalized Hurst exponents between different sea-clutter range bins would be used to determine whether the target exists. Moreover, some simulations with the real IPIX radar data have also been demonstrated in order to suooort this conclusion.     

福建沿海年平均海平面年际、年代际变化特征及预测

利用福建沿海4个验潮站实测潮位资料,在分析实测资料变化趋势的基础上,采用谱分析的方法分析年平均海平面的变化趋势,得到了4个站年平均海平面变化模型,并对未来50年福建沿海的海平面上升趋势进行预测。     

一种统计技术结合动力释用的沿海海雾预报方法

提出了一种利用历史相似个例查询技术,结合WRF模式输出释用的Gultepe沿海大雾业务预报方法。该方法可以较好的计算近地面大气中的液态水含量(LWC)和云滴粒子数密度(Nd)参数。利用该方法对2011—2013年的3—6月的历史沿海海雾个例进行试报,结果表明,恰当的结合统计方法和动力模式可以一定程度上克服目前数值模式不成熟的缺陷,从而提高WRF模式在大雾业务预报方面的释用水平。     

环渤海地区港口建设中的环境工程地质问题

环渤海地区地壳稳定性较差,沿海地带软土地基、沙土液化等不良工程地质问题较多,存在崩塌、滑坡、侵蚀淤积等环境地质灾害。特别是由地下水开采引起的地下水位下降漏斗、地面沉降、海水入侵等灾害严重。本文章介绍了环渤海港口工程地质环境,并就原生地质环境、次生地质环境、人为地质环境对港口建设的影响进行论述。